In blind rivets of the type shown in U.S. Pat. No. 3,148,578 as well as in U.S. Pat. Nos. 2,887,003; 3,489,056, special tools are required to push a locking collar into the head of the hollow rivet after the rivet stem has been pulled far enough to expand the sleeve tail and the rivet is installed. An example of such tool is shown in U.S. Pat. No. 3,038,626 wherein in the sequence of operations first the stem is pulled to expand the tail and set the rivet and after the work is clinched then in a second operation the tool is applied to push the collar from the outside into the head of the hollow rivet. Apart from the fact that such operation adds a separate step to the cycle of operations in setting the rivet, it also requires that the tension be maintained on the stem continuously after the setting of the rivet until the collar is pushed into a recess in the rivet head and this increases the cost of tooling and reduces the efficiency of the setting of the blind rivets.
The primary object of the invention is to provide a blind rivet wherein the collar is assembled on the stem in the hollow rivet so that as it is pulled to the rivet head, its tail is bulged into a locking recess in the rivet head in the same rivet setting operation thereby obviating the provision of the separate collar and also the operation of pushing a separate collar from outside into the head of a hollow rivet.